Transcription

1 The frying process 1

2 Frying is a unit operation which is mainly used to alter the eating quality of a food. A secondary consideration is the preservative effect that results from thermal destruction of micro-organisms and enzymes, and a reduction in water activity at the surface of the food (or throughout the food, if it is fried in thin slices). The shelf life of fried foods is mostly determined by the moisture content after frying: foods that retain a moist interior (for example doughnuts, fish and poultry products which may also be breaded or battered), have a relatively short shelf life, owing to moisture and oil migration during storage. These foods are important in catering applications and are produced on a commercial scale for distribution to retail stores, preserved by chilling and/or gas packing. Foods that are more thoroughly dried by frying, for example potato chips, maize and other potato snackfoods, have a shelf life of up to 12 months at ambient temperature. The quality is maintained by adequate barrier properties of packaging materials and correct storage conditions. 2

4 Shallow (or contact) frying This method is suited to foods with large surface-area-to-volume ratio (bacon slices, eggs, burgers and other types of pattie). Heat is transferred to the food mostly by conduction from the hot surface of the pan through a thin layer of oil. The thickness of the layer of oil varies as a result of irregularities in the surface of the food. This, together with the action of bubbles of steam which lift the food off the hot surface, causes temperature variations as frying proceeds and produces the characteristic irregular browning of shallow fried foods. Shallow frying has a high surface heat transfer coefficient ( Wm -2 K -1 ), although not uniformly across the entire surface of the food. 4

5 5

6 Deep-fat frying Heat transfer is a combination of convection within the hot oil and conduction to the interior of the food. All surfaces of the food receive a similar heat treatment, to produce a uniform colour and appearance. Deep-fat frying is suitable for foods of all shapes, but irregularly shaped food or pieces with a greater surface/mass ratio tend to absorb and entrain a greater volume of oil. Heat transfer coefficients are Wm -2 K -1 before evaporation of moisture from the surface begins, but subsequently increase to Wm -2 K -1 owing to the violent turbulence caused by steam escaping from the food. 6

7 When food is placed in hot oil, the surface temperature rises rapidly and water is vaporised as steam. The surface then begins to dry out in a similar way to that described during baking and roasting. The plane of evaporation moves inside the food, and a crust is formed. The surface temperature of the food then rises to that of the hot oil, and the internal temperature rises more slowly towards 100ºC. The rate of heat transfer is controlled by the temperature difference between the oil and the food and by the surface heat transfer coefficient. The rate of heat penetration into the food is controlled by the thermal conductivity of the food. The surface crust has a porous structure, consisting of different-sized capillaries.during frying, both water and water vapour are removed from the larger capillaries first, and replaced by hot oil. Moisture moves from the surface of the food through a boundary film of oil, the thickness of which controls the rate of heat and mass transfer. 7

HOME FREEZING GUIDE F FRESH VEGETABLES Freezing most vegetables at home is a fast, convenient way to preserve produce at their peak maturity and nutritional quality. The following links provide information

How to prepare vegetables for freezing By William Schafer, University of Minnesota Extension educator Revised 2011 VEGETABLES PREPARATION Asparagus Pick bright colored brittle stalks that snap when broken

Background: Baking Techniques Flour mixtures, e.g., muffins, cakes, cookies and breads, make up a large portion of our daily diets. These products are also an important part of our culture and how we celebrate

Energy Efficient Cooking Ways to save energy when cooking... and save money on the energy bill too Energy Efficient Cooking The way we cook, as well as using energy efficient cooking appliances, can reduce

DF260 series A B know your Kenwood deep fryer safety Never plug in the fryer before filling the bowl with oil. Keep children away during use and after - fat stays hot for a long time. Never let the cord

DIETS AND DIET MODIFICATION LIST I. LIQUIDS a. Thick Liquids Pudding: Liquids that have been thickened to a pudding consistency. They remain on the spoon in a soft mass. Honey: Liquids that have been thickened

100 Gram Fat Diet for 72 hour Fecal Fat Collection The fecal fat test will help find out if you have steatorrhea (that is, excess fat in bowel movements due to the body not being able to absorb fat). To

.4 HOW FOOD IS PRODUCED, PRESERVED AND COOKED Suggested success criteria We will explore how foods are produced, preserved and cooked. We will be able to examine food labels and the information they provide.

screen 1 Food delivery & storage 7. Rubbish bags in the way of deliveries This screen shows a delivery scene with a number of potential hazards to food safety. As a starting point students are encouraged

Science and Cooking: Problem Set 6 Due on Canvas by 11 PM on Saturday, October 25 th Please type or write your answers within this document or on a separate sheet of paper. Then save your work as either

FRUIT LEATHER Food and Agriculture Organization of the United Nations FRUIT LEATHER 1.- General information Fruit Leathers - general information Fruit leathers are dried sheets of fruit pulp which have

6 Part A Kitchen Tips and Information 7 Choose kitchen tools that work for you. Kitchen Tools Knives Choose knives that feel comfortable in your hand. A good choice is highcarbon stainless steel with blades

Hydrovection Cooking Guide Tips and tricks for getting the most from your Hydrovection oven 52776 Rev C (1/12) Your NEW Hydrovection oven is a versatile, easy to use tool that will help you produce better

COOKERY PROCESSES (COOKING METHODS) A lot of cooking methods are used in catering and hotel industry. Each is specific and has its advantages and disadvantages. The cookery processes or cooking methods

Level 2 Dysphagia Mechanically Altered* This diet consists of foods that are moist, soft-textured and easily formed into a bolus. All foods on Level 1 are. Meats and other select foods may be ground or

High Altitude Food Preparation Newcomers to Colorado or those traveling to the mountains are often surprised when favorite recipes made perfectly at sea level fail to produce expected results when made

The Effects of Different Oils during Deep Fat Frying of Doughnut Holes on Sensory and Quantitative Evaluations By: Julie Sankbeil Abstract The purpose of this experiment was to observe sensory qualities

The Eatwell Plate healthyfutures.nhs.uk/llb A balanced diet is important for good health. It can help you to manage your weight and increase your wellbeing, whilst also reducing the risk of heart disease,

Lancashire hotpot with Meantime beer-braised cockles and cabbage Phil Fanning This isn t your average Lancashire hotpot so be prepared! Phil Fanning s deconstructed version includes an array of brilliantly

TIPS AND TRICKS 1) If the white gelatin base becomes translucent, it means that the gelatin is either too hot or in need of titanium. 2) Freezing the gelatin will retain the shape but change the texture

Easy Iron-rich Meals for Babies and Toddlers Recipes suitable from 6 months Young babies and toddlers need plenty of iron in their diets to ensure healthy mental and physical development. In fact, babies

Detox Menu Guide We want you to have the best results possible while doing our detox. If your goal is weight loss, then eating the right foods and exercising moderately will help boost your results and

Supporting School Food Guidelines information for parents and caregivers HEALTHY STUDENTS HEALTHY SCHOOLS 2008 3 Healthy choices available in our schools This brochure provides parents and caregivers with

#1 The Thaw Law Never defrost meat at room temperature. Fight BAC! Thaw meat in the refrigerator or in the microwave if you re cooking it immediately. If raw meat is left at room temperature over two hours,

Low Fat Diet after Cardiac Surgery With or Without Chyle Leak What is chyle? Chyle (sounds like kyle) is a milky white fluid that contains protein, fat, cholesterol, lymphocytes, and electrolytes. It is

INFORMATION Hygiene Rules in the Catering Sector More than 100,000 cases of illness are reported every year in Germany that may have been caused by microorganisms in food, in particular bacteria, viruses

STANDARD OPERATING PROCEDURE S (SOP S) FOR HAZARDOUS ANALYSIS CRITICAL CONTROL POINT (HACCP) PLANS RECEIVING: All food must be from approved sources. Foods must be wholesome and not adulterated. No home-prepared

Piqsbury Wedding Cake Guide forward Whether you are baking your first wedding cake or are a professional baker, Pillsbury can help you make your celebration a success. By using Pillsbury Cake Mix you will

Recipes Sensational Holiday Recipes For a variety of reasons, many individuals experience dysphagia, or difficulty swallowing, and therefore require liquids or soft consistency foods to meet their nutrition

Dr. Albrecht Kaupp Page 1 The soot and scale problems Issue Soot and scale do not only increase energy consumption but are as well a major cause of tube failure. Learning Objectives Understanding the implications

A Correlation of Foundations of Restaurant Management & Culinary Arts Levels One & Two, 2011 Virginia Tasks and Competencies for Culinary Arts I Level INTRODUCTION This document demonstrates how well Pearson

One great mix, lots of delicious recipes Introducing our Soft Bap Mix Simplicity and versatility are the hallmarks of. The basis of a wide variety of both sweet and savoury dishes, it makes just as good

Common Baking Ingredients With the following seven categories of ingredients you can make almost every type of baked good. 1. Flour a. Examples: Wheat (white or whole), rice, corn b. Purpose in baking:

HOW MUCH SODIUM DO FOODS CONTAIN? Most of the in our diet (approx. 75%) comes from processed foods. A preference for salty foods is acquired through frequent exposure and not an inborn taste preference.

Heart Healthy Diet: Tips for Lowering Cholesterol and Fat in Your Diet Cholesterol Saturated Fats Polyunsaturated and Mono-unsaturated Fats This fat-like substance is needed for good health. However, high

Safe Food Handling For Children Ages 5 & Under Food Safety Information For Children Ages 5 & Under Children ages five and under are at an increased risk for complications from food poisoning (foodborne

The Incredible Edible Egg The largest single chicken egg ever laid weighed a pound with a double yolk and a double shell! The record for omelet making in the Guiness Book of World s Records was: 427 omelets

how food is produced how food is produced Theme An introduction to the origins of food products, with videos showing the origins and production of different foods. Aim For children to develop an understanding

S500 Trust the best Recipes S500 Trust the best S500 is a range of all purpose improvers for all types of bread and processes. It provides dough tolerance and security during all stages of the bread making

Nutrition: PECANS Pecans are a good source of potassium, thiamine, zinc, copper, magnesium, phosphorous, niacin, folic acid, iron, and vitamin B6, and also a good source of fiber. The fats are composed